<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            display: flex;

            justify-content: flex-start;
            /* 默认为沿主轴左对齐 */

            justify-content: flex-end;
            /*沿主轴右对齐*/

            justify-content: center;
            /*居中对齐*/

            justify-content: space-between;
            /*在弹性盒子之间产生空白间距,父级剩下尺寸分配为间距*/

            justify-content: space-around;
            /*在弹性盒子两侧产生空白间距,父级剩下尺寸分配为间距*/
            /*盒子之间距离是两侧两倍*/

            justify-content: space-evenly;
            /*在弹性盒子两侧产生空白间距,父级剩下尺寸分配为间距*/
            /*各个间距相等*/

            height: 300px;
            border: 1px solid #000;
        }

        .box div {

            width: 200px;
            height: 100px;
            background-color: pink;
        }
    </style>
</head>

<body>
    <div class="box">
        <div>1</div>
        <div>2</div>
        <div>3</div>
    </div>

</body>

</html>